Hydrothermal Synthesis and Crystal Structure of a Tungstovanadate: [4,4′-bipyH2][4,4′-bipyH]2[VW12O40] • 4,4′-bipy • 7.5H2O

An organic-inorganic hybrid Keggin compound, [4,4'-bipyH(2)][4,4'-bipyH](2)[VW12O40] center dot 4,4'-bipy center dot 7.5H(2)O (bipy-bipyridine) (1), has been prepared under hydrothermal conditions and characterized by IR spectroscopy, single crystal X-ray diffraction, thermal analysis, and ESR spectroscopy. 1 crystallized in the monoclinic space group P2(1)/c with a = 18.7350(15) angstrom, b = 14.0253(12) angstrom, c = 26.434(2) angstrom, beta = 105.0810(10)degrees, V = 6706.6(10) angstrom(3) and Z = 4. The crystal structure of 1 consists of diprotonated and monoprotonated 4,4'-bipyridine cations, free 4,4'-bipyridine molecule, lattice water molecules, and a typical Keggin-type polyoxoanion [VW12O40](4-). The polyoxoanion is constructed by four {W3O16} trinuclear groups, each of which is made up of three edge-sharing {WO6} octahedra, and the {VO4} tetrahedron is in the center of the cage.